HEAT SINK AND METHOD FOR PRODUCING A HEAT SINK

• US 20090139690A1
• Filed: 11/25/2008
• Published: 06/04/2009
• Est. Priority Date: 11/29/2007
• Status: Abandoned Application

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Eckhardt, Bernd, MAERZ, Martin, Egelkraut, Sven, Amesoeder, Simon, Zeltner, Stefan, Tchobanov, Dimitar
• Application Number:
  US12/323,429
• Publication Number:
  US 20090139690A1
• Time in Patent Office: Days
• US Class Current: 165/80.200
• CPC Class Codes: H01L 23/367 Cooling facilitated by shape of device H01L23/38, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence
• CPC Class Codes: H01L 23/3672 Foil-like cooling fins or heat sinks being part of lead-frames H01L23/49568
• CPC Class Codes: H01L 23/373 Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 7/20509 Multiple-component heat spreaders; Multi-component heat-conducting support plates; Multi-component non-closed heat-conducting structures
• CPC Class Codes: Y10T 29/4935 Heat exchanger or boiler making
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A heat sink includes a base body of an electrically insulating material and one or several metallic molded parts having a mounting portion and a heat-transfer portion, wherein the heat-transfer portion is mechanically connected to the base body. The heat sink can be inserted on a printed circuit board having several heat sources that can be at different electrical potentials, wherein the mounting portions of the molded parts are soldered to respective heat sources or close to the respective heat sources.

Claims

1. A heat sink, comprising:

a base body provided with structures for increasing a heat-dissipating surface;

a metallic molded part comprising a mounting portion, which is implemented to be mounted to or close to a heat source, and a heat-transfer portion, wherein at least the heat-transfer portion is mechanically connected to the base body,

wherein the base body is made of an electrically insulating material, or

wherein the base body is conductive and is electrically insulated from the metallic molded part,

wherein the mounting portion protrudes from the base body and comprises a lug extending in an angle with regard to the heat-transfer or several pins, which are implemented to be inserted in vias of a printed circuit board on which the heat source is disposed.

2. The heat sink according to claim 1, wherein the electrically insulating material of the base body comprises plastic provided with thermally conductive filling materials.

3. The heat sink according to claim 1, wherein the base body and the metallic molded part are produced by a plastic injection molding process and are connected to each other.

4. The heat sink according to claim 1, wherein the metallic molded part is adhered to a surface of the base body.

5. The heat sink according to claim 1, wherein the metallic molded part is screwed, crimped or connected in another form-fitting manner to the base body.

6. The heat sink according to claim 1, wherein the metallic molded part is provided with openings surrounded by the electrically insulating material of the base body.

7. The heat sink according to claim 1, wherein the metallic molding part is provided with an adhesive layer.

8. The heat sink according to claim 1, wherein the electrically insulating material of the base body comprises a multilayer structure.

9. The heat sink according to claim 1, wherein the electrically insulating material of the base body comprises a multilayer structure, which is produced by inserting and molding electrically insulating films with an injection molding process.

10. The heat sink according to claim 1, wherein the electrically insulating material of the base body comprises a multilayer structure, which is produced by a skin-core-skin structure during the injection molding process, and the skin comprises electrically non-conductive plastic and the core electrically conductive plastic.

11. The heat sink according to claim 1, wherein the metallic molded part comprises an insulator coating, and is embedded in the base body together with the insulator coating.

12. The heat sink according to claim 11, wherein the metallic molded part has been immersed in polyimide and has subsequently been molded.

13. The heat sink according to claim 1, which is mounted on a printed circuit board like a wired device (THD device).

14. The heat sink according to claim 1, which is mounted on a printed circuit board like an SMD device.

15. The heat sink according to claim 1, wherein the mounting portion is implemented as a lug, which projects in an angle with regard to the heat-transfer portion.

16. The heat sink according to claim 1, which is implemented to form a housing part for an electronic circuit.

17. The heat sink according to claim 1, which comprises additional fixtures, which are implemented to connect the metallic molded part with or without the printed circuit board connected thereto to a housing part.

18. The heat sink according to claim 1, which comprises additional fixtures, such as latching lugs, and is shaped such that the same can be inserted in a recess provided therefore in a housing, and is held in a stable manner by latching of the additional fixtures.

19. The heat sink according to claim 1, wherein the base body comprises a lamellar heat dissipation structure, which is thermally coupled to the heat-transfer portion.

20. The heat sink according to claim 1 comprising a further metallic molded part, which is electrically insulated from the metallic molded part.

21. The heat sink according to claim 1, wherein the lug is implemented as resilient lug, which comprises such an elasticity that the same is elastically deflected by a difference of coefficients of thermal extension between the heat sink and the heat source.

22. The heat sink according to claim 1, wherein the heat-transfer portion comprises a flat shape, wherein an area of the heat-transfer portion is at least five times the size of an area of a heat source of a circuit carrier on or close to which the mounting portion can be mounted.

23. The heat sink according to claim 1, wherein the mounting portion is implemented in a solderable manner.

24. The heat sink according to claim 23, wherein the mounting portion comprises a surface characteristic wettable for solder.

25. A method for producing a heat sink, comprising:

mounting a metallic molded part comprising a mounting portion, which is implemented to be mounted to or close to a heat source, and a heat-transfer portion, which borders on the mounting portion, to a base body provided with structures for increasing a heat-dissipating surface, wherein the base body comprises an electrically insulating material, or wherein the base body is conductive and electrically insulated from the metallic molded part, wherein the mounting portion protrudes from the base body and comprises a lug extending in an angle with regard to the heat-transfer or several pins, which are implemented to be inserted in vias of a printed circuit board on which the heat source is disposed.

26. The method according to claim 25, wherein the electrically insulating material is plastic and the step of mounting comprises molding or casting the metallic molded part via a plastic injection molding method or a casting method.

27. The method according to claim 25, wherein the metallic molded part is produced by punching and bending.

28. The method according to claim 27, wherein the metallic molded part comprises holding ridges for a cast process prior to mounting the metallic molded part, wherein the holding ridges are removed after casting or molding the metallic molded part.

29. The method according to claim 25, wherein the metallic molded part is immersed into an insulator, such as polyimide, whereupon the step of mounting takes place by molding or casting, such that the metallic molded part is electrically insulated from the base body and the base body is implemented in a conductive manner.

30. The method according to claim 25, wherein several molded parts are provided, the method comprising:

predetermining a heat dissipation characteristic for every heat source of a plurality of heat sources;

optimizing an area per molded part, for providing an approximation to the predetermined heat dissipation characteristic for every molded part; and

producing the molded parts after the step of optimizing and prior to the step of mounting.

32. The method according to claim 30, wherein the heat source is a device on a printed circuit board, wherein the printed circuit board comprises a conductive trace to the device, and

wherein soldering takes place by soldering the mounting portion to the conductive trace close to the device.

33. The method according to claim 32, wherein the mounting portion is soldered on the conductive trace in less than 1 cm distance from the heat source.

31. A method for inserting a heat source on a printed circuit board, comprising:

soldering a heat sink comprising;

a base body provided with structures for increasing a heat-dissipating surface;

a metallic molded part comprising a mounting portion, which is implemented to be mounted to or close to a heat source, and a heat-transfer portion, wherein at least the heat-transfer portion is mechanically connected to the base body,

wherein the base body is made of an electrically insulating material, or

wherein the base body is conductive and is electrically insulated from the metallic molded part,

wherein the mounting portion protrudes from the base body and comprises a lug extending in an angle with regard to the heat-transfer or several pins, which are implemented to be inserted in vias of a printed circuit board on which the heat source is disposed,

to or in thermal coupling to the heat source.

34. The method according to claim 31, wherein the heat sink comprises several metallic molded parts, which are connected to a base body, wherein the printed circuit board comprises several heat sources at different potentials, and wherein after a step of inserting the heat sink on the printed circuit board, mounting portions of the several metallic molded parts are soldered to or close to the respective heat sources.